Stoker link and method of making the same



Feb. 27, 1945. w. M. DUNCAN 2,370,236

STOKER LINK AND METHOD OF MAKING THE SAME Filed May 22, 1941 I IL BYWA 3M Patented Feb. 27, 1945 STQKER. LINK AND METHOD OF MAKING I THESAME WilliamM, Duncan, Alton, 111.

Application May 22, 1941, Serial No. 394,665

Claims.

This invention pertains to stokers for furnaces, and more particularly to a novel construction for a chain-grate link for such a stoker and a method of manufacturing such links.

Ghainegrate stokers have'heretofore been made almost universally with links constructed of cast iron. This has been necessary mainly on account of the special shape that such links must usually take and the fact that suchspecial shapes are easily and cheaply produced by the casting prooess. Links of steel have been used, made Icy-forging or casting. However, on account of the high cost of such links, they have been used mostly for drive links, or in special cases where requirements areexceptionally severe.

Experience has shown that cast iron links are subject to deterioration if used in a furnaceinstallation in which the links are subject to over heating. Also, when such links are accidentally overheated, they tend to buckle and sometimes grow somewhat in size. Accordingly, the reliability and smooth operation of the chain-grate are impaired when such defects appear in the links. Steel links, where they have been used, have been found to be much less subject to this tendency to deteriorate by warping or buckling when overheated. However, steel links as heretofore produced by forging or casting have been prohibitively high in cost.

One of the objects of this invention. therefore, is to provide a link construction by which the link may be constructed of steel by other than the forging or casting process.

Another object is to provide a method of construction for the manufacture of such steel links which will be cheap enough to make it practical to employ such links for stokers of the type in which cast iron links are now universally used.

Further objects will appear from the following description, taken in connection with the accompanying drawing, in which:

Figure 1 illustrates a rolled steel bar from which the stoker links may be manufactured in accordance with this invention;

Figure 2 is a verticalsection of the bar shown in Figure 1; v

Figure 3 is a side view of a link element or blank formed from the bar of Figure 1;

Figure 4 is a side view of the finished link;

Figure 5 is a section on line 5-5 of Figure 4;

Figure 6 is a face view of the combined air-stop and pivot-bearing lug to be attached to the blank of Figure 3; and

Figure 7 provides side and sectional views of a strip illustrating the manner in which the lugs of Figure 6 may be punched from such a strip.

In accordance with thisinve-ntiona stoker link of practically any desired shape may loo-produced out of bar steel at a low cost. Such a link is usually formed with a vertical web portion and an enlargedhead' portion which forms the fire bed in the assembled chain-grate. In accordance with the method of this invention, a rolledsteel bar, such as shown in Figure 1, is made by the usual rolling process. Inthis process bars ofex tended length can easily and'cheaply be made; having almost any simple cross section, and by this rolling processthese bars can be manufactured in quantity at a less cost; As shown in Figures 1 and 2, this rolledbar may be formed with a web portion 1 anda head portion 2', which is usually somewhat enlarged as compared tothe web portion I. Here the web or the head portion may be formed, as shown in Figure 2, or-thecrosssection'may bevaried to produce any desired shape of head Orweb which may be formed by the rolling process.

In accordance with this invention, link elements are formed from the rolled bar of Figure 1. This may be done by severing said bar into sections of suitable length to form the link elements. Either after severing, or simultaneously therewith, the link element may be shaped in any desired manner to provide the desired shape of link. In the link illustrated in the accompanying drawing, the link elements shown in Figure 3 may be formed by punching successive lengths from the bar of Figure 1, so that the link element also has the web portion I and the head portion 2. Simultaneously with this punching operation or subsequently, the web portion is perforated with pivot holes 3. These are adapted to receive the pivot bars on which the links are assembled to form the chain-grate.

It is usually preferable to provide such a link with means to prevent a longitudinal travel of air along the assembled chain-grate, and cast iron links are usually provided with lugs or baffles for that purpose. In accordance with this invention, such 2. lug is provided, as shown in Figure 6, having a circular bearing portion 4 perforated with a pivot hole 5 and an extension 6 providing an airstop. These lugs may be made by punching from bar stock 1, as indicated in dotted lines in Figure 7.

The link is then finished, as illustrated in Figure 4, by attaching to the link element of Fig-ure 3 one or more of the lugs shown in Figure 6. In Figure 4 two such lugs are shown attached by welding the same to the web portion l, as indicated. These lugs are placed with the pivot holes 5 thereof in registry with the pivot holes 3 of the bars. The extension 6 is positioned so as to ex-,

tend upwardly to meet the head portion 2 and to close oif the space adjacent the web and beneath said head portion against the movement of air lengthwise of the link. The thickness of the lugs may be made slightly greater than the projection of the head portion 2 beyond the web portion I, so that when assembled, as shown in Figure 5, the lugs will project slightly beyond said head portion. This structure provides that when a'plurality of these links are assembled in a chaingrate, the extra width of the lugs provides a narrow space between the head portions of laterally adjacent links when assembled in the grate. Such spaces provide draft openings for the air to pass upwardly from below the head portion 2 to the fire on the grate.

It will be seen that this invention accomplishes its objects in providing a steel link of a construction such that it may be manufactured at a cost low enough to compete with cast iron links. The method of construction is such that the component elements of the link may be manufactured in quantity at a cost very much lower than such operations as forging, and, accordingly, a method i provided for the economical manufacture of such steel links. By providing a method in which the advantages of the rolling process for forming steel bars are obtained, together with the advantages in economy of such forming operations as punching, this method provides a simple and economical procedure for forming such steel links. The finished links, being of steel, ar capable of a very much longer life than cast iron links and are not subject to deterioration from overheating to such an extent as are cast iron links.

It is obvious that various changes may be made in the details of construction and procedure within the scope of the appended claims without departing from the spirit of this invention. It is understood, accordingly, that the invention is not limited to the specific details shown and described.

The invention having thus been described, what is claimed is:

l. A stoker link comprising, a body of rolled bar-steel having a web portion and a head portion, a bar-steel air-stop lug and a weld permanently attaching said lug to said web portion.

2. A stoker link comprising, a body of rolled bar-steel having a web portion and a head portion, a combined air-stop and pivot-bearing lug of bar steel and a weld permanently attaching said lug to said web portion.

3. The method of making chain-stoker links. comprising, rolling a steel bar of extended length to a shape having a web portion and a head portion, severing the rolled bar into link-lengths to produce separate link elements and perforating the elementgwith pivot holes, and welding an air-stop lug to the link element below the head portion.

4. The method of making chain-stoker'links, comprising, rolling a steel bar of extended length to a shape having a Web portion and a head portion, punching the rolled bar into link sections and perforating the sections with pivot holes, and integrally attaching air-stop lugs to the link sections below the head portion.

5. The method of making chain-stoker links, comprising, rolling a steel bar of extended length to a shape having a web portion and a head portion, severing the rolled bar into link-lengths to produce separate link elements and perforating the elements with pivot holes, forming an airstop lug out of steel bar stock, and welding the air-stop lug to the link element below the head portion.

WILLIAM M. DUNCAN. 

